激光熔覆Stellite-6+VC混合粉末的熔覆层组织

用脉冲300 W Nd:YAG激光器、6轴机器人、5 m长的光纤、送粉系统及送粉专用喷嘴，建立了激光机器人熔覆系统.在低碳钢（SM400B）上熔覆Co基合金（Stellite-6）和碳化钒（VC）混合粉末（VC的质量分数变化范围为0~100%），并对熔覆层的形状和显微组织进行了分析.结果表明，在0~80%范围内随着混合粉末中VC的质量分数增加，VC初晶相的数量随之增加，同时熔深也随之增加；根据混合粉末中VC的质量分数的不同，熔覆层显微组织可分为两种类型，即亚共晶组织和过共晶组织；亚共晶组织由富钴的γ相与共晶组织组成，过共晶组织由初晶VC相与共晶组织组成.

Organization of clad layer using mixed powder of stellite 6 and VC

A laser robot cladding system was set by using pulsed 300 W Nd: YAG laser facility, 6-axis robot, a optical fiber of 5 m in length, powder feeding system and special nozzle for powder supply. Stellite 6 alloy and VC mixed powder were cladded on mild steel (SM400B) plate. Shape of clad layer, microstructure and performance of clad layer were investigated by changing the weight fraction of VC in the range of 0 to 100%. The experimental results demonstrated that as the weight fraction of VC in the powder mixture increases in the range of 0 to 80%, the amount of primary solidified VC phase and penetration depth increased. Depending on the weight fraction of VC in the powder, the resultant microstructures can be divided into two types - hypoeutectic structure containing primary Co-richγ phase with eutectic structure and hypereutectic structure containing primary VC, complex carbides and eutectic structure.